Practical Application Of Plant Disease Resistance Metabolites In Wheat Disease Control

Soil-borne diseases seriously affect crop yield and bring great challenges to the sustainable development of agriculture.At present,the rapid and efficient method for soil-borne diseases is chemical control.Long-term chemical control will not only enhance the resistance of pathogens,but also cause environmental pollution and soil ecological imbalance.Therefore,the development of new green and safe agents is an urgent requirement for agricultural sustainable development.As an important lead source of green fungicides,plant-derived disease resistance metabolites are widely found in nature.In this study,three plant-derived disease resistance metabolites with known antibacterial activity were screened,and tetraethylphenol was selected as the main research object to study the prevention and application of three wheat soil-borne diseaseswheat scab,wheat stem rot and wheat total corrosion disease.The main study results are presented as follows:1.Screening of plant source fungicide.The indoor virulence results of three plant-derived metabolites against three wheat soil-borne disease pathogens showed that compared with 4-Ethylphenol,lauric acid and linalol,4-Ethylphenol was more virulent against Fusarium graminearum,Fusarium pseudograminearum and Take-all pathogen of wheat,EC₅₀were 73.347 mg/L,49.017 mg/L and 21.487 mg/L,respectively.In conclusion,we selected 4-Ethylphenol for subsequent experiments.2.Bacteriostatic pathway of 4-Ethylphenol.4-Ethylphenol can inhibit radial growth of F.pseudograminearum,destroy cell membrane of F.pseudograminearum,and have teratogenic effect on conidia and their germ tube.The results of indoor virulence determination of 4-Ethylphenol on F.pseudograminearum showed that the EC₅₀was 49.017 mg/L and 100 mg/L of 4-Ethylphenol inhibited F.forangermination by 95.92%.3.4-Ethylphenol was used in a combination with lauric acid.The virulence of4-Ethylphenol to F.pseudograminearum(EC₅₀=49.017 mg/L)was much higher than that of lauric acid(EC₅₀=336.394 mg/L);however,in the inhibition of conidial germination,the inhibition rate of 100 mg/L 4-Ethylphenol was 95.92%,while the inhibition rate of 25 mg/L lauric acid reached 91.99%.This provides a new idea for the control of wheat diseases in field:combining lauric acid and tetraethylphenol,inhibiting the mycelium of F.pseudowinee and its conidia,and effectively preventing Fusarium crown rot（FCR）caused by F.pseudograminearum.4.Effect of 4-Ethylphenol and lauric acid on plant safety and yield.The combination of lauric acid and tetraethylphenol can promote wheat seed germination,plant growth,tillering and the expression of wheat cold resistance gene CBFIVd-D22.In terms of yield,the yield of different treatment groups increased compared with that of the photographic groups.Among them,in the group with the best yield effect,the number of ears and grains in the group increased compared with the control,and the yield rate reached 49.27%;In the control of fusarium crown rot,all treatment groups could control wheat stem base rot compared with the control.The strain rate of tetraethylphenol treatment group was 81.63%and the disease index prevention effect was 86.47%,indicating that 4-Ethylphenol achieved the purpose of preventing and controlling wheat stem rot by reducing the strain rate and reducing the disease index.The effect of lauric acid and tetraethylphenol before seeding on wheat yield was shown that:all treatments showed an increase in spike count per square meter compared to controls.5.4-Ethylphenol protection against soil-borne diseases in wheat.4-Ethylphenol effectively inhibited the growth of F.graminearum,EC₅₀was 73.347 mg/L.In the field of wheat scab in Zhenjiang,the effect of spraying 10 g 4-Ethylphenol per mu before wheat flowering reached 86.80%.4-Ethylphenol seed treatment can effectively prevent fusarium crown rot.6.Relationship between antibacterial activity of 4-Ethylphenol and its homologues and alkyl carbon chain length.The antibacterial effect was:4-Butylphenol(EC₅₀=12.878 mg/L)>4-Ethylphenol(EC₅₀=21.594 mg/L)>4-Propylphenol(EC₅₀=48.954 mg/L)>4-Hydroxytoluene(EC₅₀=4412.780 mg/L).This indicates that the inhibition of F.pseudograminearum was enhanced with the length of the alkyl carbon chain.The water solubility of the four homogs was also related to the alkyl carbon chain length,namely:4-Hydroxytoluene>4-Propylphenol>4-Ethylphenol>4-Butylphenol,in which 4-Hydroxytoluene 20 g/L（20℃）,4-Propylphenol 4.9 g/L（25℃）,4-Ethylphenol 1.427 g/L（25℃）,and 4-Butylphenol is insoluble in water.We selected 4-Propylphenol with better antibacterial effect and soluble in water,and performed the subsequent mixing experiments with4-Ethylphenol and lauric acid.7.Compound and screen the optimal formula.Among the six combinations,4-Ethylphenol:lauric acid（3:1）combination showed strong virulence to F.graminearum,F.pseudograminearum and Take-all pathogen of wheat,with EC₅₀of7.431 mg/L,20.170 mg/L and 21.801 mg/L,respectively.In this study,three plant-derived disease resistance metabolites with known bacteriostatic activity were screened.It analyzed the effectiveness of 4-Ethylphenol in the control of three soil-borne diseases of wheat,wheat scab,wheat stem rot and wheat total corrosion disease.This study further investigated the inhibition pathway of 4-Ethylphenol and the effect of 4-Ethylphenol in combination with lauric acid on plant safety and yield.In addition,the relationship between the antibacterial activity of 4-Ethylphenol and its congeners and the length of alkyl carbon chains was investigated,and the optimal formulation was screened to provide new ideas for sustainable agricultural development.